1. Field of the Invention
The present invention relates to a control rod driving simulator for verification of a control rod driving mechanism control system of an atomic power plant, in particularly to a control rod driving simulator wherein a driving mechanism having a same condition as a control rod driving mechanism equipped to a reactor core is connected to a control rod driving mechanism control system in executing a preliminary operational test, so that it is possible to check the problems occurring in the control rod driving mechanism control system in advance in a process of a preliminary operation and thus to obtain confidence and stability of the control rod driving mechanism control system without causing a change of a degree of nuclear reaction of the reactor core as the control rod moves.
2. Description of the Related Art
Generally, a control rod driving mechanism of an atomic reactor serves to control a nuclear reaction of the atomic reactor by withdrawing or inserting a control rod using electromagnetic force and thus to regulate electrical output of an atomic power plant.
The control rod is stepwisely withdrawn or inserted and a series of sequence operations having 6˜7 stages should be sequentially carried out to move one step. When any operation of the sequence operations is not properly carried out in a mechanical or electrical manner, it can occur that the control rod is not moved or drops downwards.
Since these situations are very important in connection with a safety work of the atomic power plant and an efficient utilization of nuclear fuel, a check of the sequence operations is the most important matter in designing and embodying a control rod control mechanism. To check the sequence operations, a method of signal-processing a wave form of current flowing in a coil member and thus determining whether the control rod is operated or not is recently used.
The prior simulator for verifying the method cannot provide a same load as a control rod driving mechanism that is actually equipped to an atomic reactor of an atomic power plant, because it carries out verification only with a control rod driving mechanism having not a control rod. Accordingly, it is impossible to execute a correct verification of a control rod driving mechanism control system.
The above-mentioned control rod driving mechanism consists of various coil members and the control rod driving mechanism control system comprises a control circuit and a power circuit element, etc. and is connected to the control rod driving mechanism.
In the prior simulator, upper and lower parts thereof are closed and cooling water is supplied therein by a separate pump. The cooling water is filled up in the whole simulator. And then, two coil members are mounted to each of exterior upper and lower parts of the simulator, respectively.
When an electric power is applied to the coil members, the temperature thereof is increased. Since electromagnetic properties such as resistance are changed as the temperature is increased, it is required to maintain the temperatures of the coil members of the simulator to be same as those of the coil members of an actual control rod driving mechanism of an atomic power plant. Accordingly, when the temperatures of the coil members are increased above the actual temperatures, a cooling fan is provided to cool it. The cooling fan is initially operated at low speed. When the operation time is 30 minutes or more, or the atmosphere temperature is 32.22° C. or more, the fan is set to operate at high speed. Such a setting is carried out in a manual manner by the worker.
Since the prior cooling fan is operated by hand, there is a problem that the cooling fan cannot cool the coil members by properly operating as the temperatures of the coil members are changes. In addition, as mentioned above, since the simulator is not provided with a control rod used in an actual control rod driving mechanism, the same load as an actual state cannot be provided. Therefore, it was impossible to carry out a correct verification and maintenance of the control rod driving mechanism control system.
These verification and maintenance operations are meant to set, regulate and verify voltage applied from the control rod driving mechanism control system. According to the prior simulator, since it is impossible to distinguish a correct timing of applied voltage or a magnitude of necessary applied voltage, when the simulator is applied to the control rod driving mechanism of an actual atomic reactor, it is impossible to correctly verify whether the control rod driving mechanism control system is properly operated or not.